(a) Statement of the Invention
The present invention relates to difunctional single terminated macromolecular monomers; condensation chemically joined, phase separated graft copolymers comprised of polymeric sidechains and condensation type polymeric backbones; and their preparation.
(B) Description of the Prior Art
There have been many attempts by prior art workers to combine the properties of various polymers with other dissimilar polymers by either chemical or mechanical means. Many times these copolymers have been prepared only with difficulty due to the incompatibility of the polymers to be combined.
One way in which this objective has been sought involves the preparation of block or graft copolymers. In this way, two different polymeric segments, normally incompatible with one another, are joined together chemically to give a sort of forced compatibility. In such a copolymer, each polymer segment continues to manifest its independent polymer properties. Thus, the block or graft copolymer in many instances possesses a combination of properties not normally found in a homopolymer or a random copolymer.
One method of combining the properties of condensation-type polymers with styrene, olefin or diene polymers is disclosed in British Patent Specification No. 1,262,792. This patent describes the preparation of block copolymers by reacting a dicarbanion living polymer prepared by anionic polymerization with a preformed polymeric segment of a condensation-type polymer having a functional group on each end of the polymer capable of reacting with the dicarbanion. Thus, by the method described in the '792 patent, polymers having blocks of, for example, polystyrene and polyester are prepared.
Another method for the forced combination of dissimilar polymeric materials is disclosed in U.S. Pat. No. 3,786,116 to Milkovich et al. The patent describes the preparation of graft copolymers by first preparing a monofunctional living polymer by anionic polymerization which is then reacted with a terminating agent to prepare a macromolecular monomer with a copolymerizable end group. The copolymerizable end group is subsequently copolymerized with a backbone-forming comonomer to form the graft copolymer.
The '116 patent discloses the termination of an ethylene oxide capped living polymer with haloalkyl maleic anhydride or haloalkyl maleate esters. It is suggested that the anhydride and ester groups be converted to carboxyl groups and that the resulting dicarboxylic terminated polymers be reacted with glycols or diamines to form polyesters and polyamides having a graft copolymer structure. The reaction of such a dicarboxylic macromolecular monomer with a glycol or diamine as disclosed in the '116 patent, however, only results in backbones composed of the corresponding polyester or polyamide. It would be desirable, however, to prepare chemically joined, phase separated graft copolymers having as a polymeric backbone phase the reaction product of at least two condensible comonomers and chemically joined thereto a sidechain phase consisting of a self-reinforcing polymeric entity which provides a thermolabile cross-link to the copolymer. Such copolymers are not disclosed in the '116 patent as described above.
Another copolymerizable end group disclosed in U.S. Pat. No. 3,786,116 is a glycol end group which is prepared by terminating the monofunctional living polymer with epichlorohydrin and subsequently hydrolyzing the resulting epoxide end group to form the glycol or diol end group. It is suggested that this glycol terminated macromolecular monomer can be reacted with a dicarboxylic acid or diisocyanate prepolymer to form a graft copolymer with a polyamide or polyurethane backbone. The glycol or diol end group disclosed in the '116 patent, however, made by using the epichlorohydrin end group contains both a primary and a secondary hydroxy group. The primary and secondary hydroxy groups each have different rates of condensation in the condensation reaction with the backbone forming dicarboxylic acids or diisocyanates. Moreover, the glycol or diol terminated macromolecular monomers prepared from epichlorohydrin terminated macromolecular monomers do not form as a symetrical structure as is desired in a condensation-type copolymer.